self stabilizing platform

Hi, i have been working on this project for a while.I am stuck at a point. the platform seems to be responding well to pitch values but it seems to be responding to roll values in one direction and doesnt respond to the other direction.Mostly i am using the code from jeff rowbergs DMP6 sketch and the only changes i made are as follows:

#include <Servo.h>
Servo servoY;
Servo servoX;

// added in setup:
servoY.attach(9);
servoX.attach(10);

// added in the end of loop() function:
myservoY.write(90+int(ypr[2] * 180/M_PI));
myservoX.write(90+int(ypr[1] * 180/M_PI));

i think the problem is in the last two lines of the code

thanks in advance

Post your full code using code tags.

#include <Servo.h>

Servo myservoY; // 
Servo myservoX;
// I2Cdev and MPU6050 must be installed as libraries, or else the .cpp/.h files
// for both classes must be in the include path of your project
#include "I2Cdev.h"

#include "MPU6050_6Axis_MotionApps20.h"
//#include "MPU6050.h" // not necessary if using MotionApps include file

// Arduino Wire library is required if I2Cdev I2CDEV_ARDUINO_WIRE implementation
// is used in I2Cdev.h
#if I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE
    #include "Wire.h"
#endif

// class default I2C address is 0x68
// specific I2C addresses may be passed as a parameter here
// AD0 low = 0x68 (default for SparkFun breakout and InvenSense evaluation board)
// AD0 high = 0x69
MPU6050 mpu;
//MPU6050 mpu(0x69); // <-- use for AD0 high




// uncomment "OUTPUT_READABLE_YAWPITCHROLL" if you want to see the yaw/
// pitch/roll angles (in degrees) calculated from the quaternions coming
// from the FIFO. Note this also requires gravity vector calculations.
// Also note that yaw/pitch/roll angles suffer from gimbal lock (for
// more info, see: http://en.wikipedia.org/wiki/Gimbal_lock)
#define OUTPUT_READABLE_YAWPITCHROLL

#define LED_PIN 13 // (Arduino is 13, Teensy is 11, Teensy++ is 6)
bool blinkState = false;

// MPU control/status vars
bool dmpReady = false;  // set true if DMP init was successful
uint8_t mpuIntStatus;   // holds actual interrupt status byte from MPU
uint8_t devStatus;      // return status after each device operation (0 = success, !0 = error)
uint16_t packetSize;    // expected DMP packet size (default is 42 bytes)
uint16_t fifoCount;     // count of all bytes currently in FIFO
uint8_t fifoBuffer[64]; // FIFO storage buffer

// orientation/motion vars
Quaternion q;           // [w, x, y, z]         quaternion container
VectorInt16 aa;         // [x, y, z]            accel sensor measurements
VectorInt16 aaReal;     // [x, y, z]            gravity-free accel sensor measurements
VectorInt16 aaWorld;    // [x, y, z]            world-frame accel sensor measurements
VectorFloat gravity;    // [x, y, z]            gravity vector
float euler[3];         // [psi, theta, phi]    Euler angle container
float ypr[3];           // [yaw, pitch, roll]   yaw/pitch/roll container and gravity vector

// packet structure for InvenSense teapot demo
uint8_t teapotPacket[14] = { '

, 0x02, 0,0, 0,0, 0,0, 0,0, 0x00, 0x00, ‘\r’, ‘\n’ };

// ================================================================
// ===              INTERRUPT DETECTION ROUTINE                ===
// ================================================================

volatile bool mpuInterrupt = false;    // indicates whether MPU interrupt pin has gone high
void dmpDataReady() {
    mpuInterrupt = true;
}

// ================================================================
// ===                      INITIAL SETUP                      ===
// ================================================================

void setup() {
    // join I2C bus (I2Cdev library doesn’t do this automatically)
    #if I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE
        Wire.begin();
        TWBR = 24; // 400kHz I2C clock (200kHz if CPU is 8MHz)
    #elif I2CDEV_IMPLEMENTATION == I2CDEV_BUILTIN_FASTWIRE
        Fastwire::setup(400, true);
    #endif

//Attach servo

myservoY.attach(9); // Attach Y servo to pin 9
  myservoX.attach(8);

// initialize serial communication
    // (115200 chosen because it is required for Teapot Demo output, but it’s
    // really up to you depending on your project)
    Serial.begin(115200);
    while (!Serial); // wait for Leonardo enumeration, others continue immediately

// NOTE: 8MHz or slower host processors, like the Teensy @ 3.3v or Ardunio
    // Pro Mini running at 3.3v, cannot handle this baud rate reliably due to
    // the baud timing being too misaligned with processor ticks. You must use
    // 38400 or slower in these cases, or use some kind of external separate
    // crystal solution for the UART timer.

// initialize device
    Serial.println(F(“Initializing I2C devices…”));
    mpu.initialize();

// verify connection
    Serial.println(F(“Testing device connections…”));
    Serial.println(mpu.testConnection() ? F(“MPU6050 connection successful”) : F(“MPU6050 connection failed”));
/*
    // wait for ready
    Serial.println(F("\nSend any character to begin DMP programming and demo: "));
    while (Serial.available() && Serial.read()); // empty buffer
    while (!Serial.available());                // wait for data
    while (Serial.available() && Serial.read()); // empty buffer again
*/
    // load and configure the DMP
    Serial.println(F(“Initializing DMP…”));
    devStatus = mpu.dmpInitialize();

// supply your own gyro offsets here, scaled for min sensitivity
    mpu.setXGyroOffset(220);
    mpu.setYGyroOffset(76);
    mpu.setZGyroOffset(-85);
    mpu.setZAccelOffset(1788); // 1688 factory default for my test chip

// make sure it worked (returns 0 if so)
    if (devStatus == 0) {
        // turn on the DMP, now that it’s ready
        Serial.println(F(“Enabling DMP…”));
        mpu.setDMPEnabled(true);

// enable Arduino interrupt detection
        Serial.println(F(“Enabling interrupt detection (Arduino external interrupt 0)…”));
        attachInterrupt(0, dmpDataReady, RISING);
        mpuIntStatus = mpu.getIntStatus();

// set our DMP Ready flag so the main loop() function knows it’s okay to use it
        Serial.println(F(“DMP ready! Waiting for first interrupt…”));
        dmpReady = true;

// get expected DMP packet size for later comparison
        packetSize = mpu.dmpGetFIFOPacketSize();
    } else {
        // ERROR!
        // 1 = initial memory load failed
        // 2 = DMP configuration updates failed
        // (if it’s going to break, usually the code will be 1)
        Serial.print(F(“DMP Initialization failed (code “));
        Serial.print(devStatus);
        Serial.println(F(”)”));
    }

// configure LED for output
    pinMode(LED_PIN, OUTPUT);
}

// ================================================================
// ===                    MAIN PROGRAM LOOP                    ===
// ================================================================

void loop() {
    // if programming failed, don’t try to do anything
    if (!dmpReady) return;

// wait for MPU interrupt or extra packet(s) available
    while (!mpuInterrupt && fifoCount < packetSize) {
        // other program behavior stuff here
        // .
        // .
        // .
        // if you are really paranoid you can frequently test in between other
        // stuff to see if mpuInterrupt is true, and if so, “break;” from the
        // while() loop to immediately process the MPU data
        // .
        // .
        // .
    }

// reset interrupt flag and get INT_STATUS byte
    mpuInterrupt = false;
    mpuIntStatus = mpu.getIntStatus();

// get current FIFO count
    fifoCount = mpu.getFIFOCount();

// check for overflow (this should never happen unless our code is too inefficient)
    if ((mpuIntStatus & 0x10) || fifoCount == 1024) {
        // reset so we can continue cleanly
        mpu.resetFIFO();
        Serial.println(F(“FIFO overflow!”));

// otherwise, check for DMP data ready interrupt (this should happen frequently)
    } else if (mpuIntStatus & 0x02) {
        // wait for correct available data length, should be a VERY short wait
        while (fifoCount < packetSize) fifoCount = mpu.getFIFOCount();

// read a packet from FIFO
        mpu.getFIFOBytes(fifoBuffer, packetSize);
       
        // track FIFO count here in case there is > 1 packet available
        // (this lets us immediately read more without waiting for an interrupt)
        fifoCount -= packetSize;

#ifdef OUTPUT_READABLE_YAWPITCHROLL
            // display Euler angles in degrees
            mpu.dmpGetQuaternion(&q, fifoBuffer);
            mpu.dmpGetGravity(&gravity, &q);
            mpu.dmpGetYawPitchRoll(ypr, &q, &gravity);
            //Serial.print(“ypr\t”);
            //Serial.print(ypr[0] * 180/M_PI);
            //Serial.print("\t");
            //Serial.print(ypr[1] * 180/M_PI);
              // Rotation around Y
            //Serial.print("\t");
            //Serial.println(ypr[2] * 180/M_PI);
            myservoY.write(90+int(ypr[2] * 180/M_PI)); 
        myservoX.write(90+int(ypr[1] * 180/M_PI));
        #endif

// blink LED to indicate activity
        blinkState = !blinkState;
        digitalWrite(LED_PIN, blinkState);
    }
   
}

Try changing:

 myservoY.write(90+int(ypr[2] * 180/M_PI)); 
  myservoX.write(90+int(ypr[1] * 180/M_PI));

to:

 myservoY.write(90+int(ypr[2] * 180.0/M_PI));   
  myservoX.write(90+int(ypr[1] * 180.0/M_PI));